GB375923A - Improvements in or relating to key board mechanism for telegraph apparatus - Google Patents

Abstract

375,923. Selective punching machines. CREED & CO., Ltd., Telegraph Works, Croydon.-(Teletype Corporation; 1400, Wrightwood Avenue, Chicago, U.S.A.) April 23, 1931, No. 12036. [Class 31 (ii).] A keyboard arrangement, for the perforation of a tape in accordance with the code combinations of a signal, employs signal keys associated with shift keys and locking means arranged to prevent the simultaneous operation of two or more signal keys, but to permit the simultaneous depression of a signal key and a shift key. The keyboard arrangement is similar to that of an ordirary typewriter, and the shift keys move solely a single additional or sixth selector bar, which is also moved by the depression of some of the signal keys, normally corresponding tc shift characters with a fiveunit system. All the key levers 11 engage one or more of the bars 25 for selective movement and additionally a universal bar 44, whilst the levers 11 corresponding to some of the characters also engage can. projections 28<1> on the sixth bar 251 to move it from the position in which it is normally held by a spring 29. The levers 11<1> of the shift and lock shift keys 17, 18 respectively, invariably engage a cam lug 281 on the bar 25, but are arranged opposite notches in the bars 25, and the universal bar 44 which may be operated by the simultaneous depression of a shift character key and the corresponding lever 11. Owing to the arrangement of the inclined cam lugs 28 on the bars 25, the simultaneous depression of two or more signal keys is pievented since the arrangement of the inclined faces on the bars 25 under each key lever will be different and for the depression of a second key there will always be at least one bar which would have to be moved in a direction opposite to that in which it has been moved by the depression of the first key. When the lock-shift key 18 is operated, the bar 11<1> is held in the depressed position by a pin 20 which engages with a notch in a pivoted member 19. The lock-shift is removed by actuating shift key 17 which, through a member 22, rotates the member 19 to release the lever 11<1>. For effecting the perforation of the tape, the code bars 25, 25<1> position auxiliary selector bars 48, carried on an anvil 51 formed as the armature of an electromagnet 55, with respect to punch rods 49. The universal bar is arranged to energize the electromagnet 55 and the tape is stepped forward by a ratchet wheel 58 actuated by a pawl 57 on the return stroke of the armature.